Passenger vehicles may utilize a variety of different structures or techniques to limit, minimize, or otherwise reduce the amount of sound transmitted from locations outside of the passenger cabin to its interior. Minimizing the noise or acoustic vibrations that certain vehicle components emit is one technique. For example, engines, transmissions, exhaust systems, tires, or other components may be designed to be relatively quiet when in use so that passenger cabin noise is lessened. Another technique is to provide components that attenuate vibrations that would otherwise reach the passenger cabin by absorbing and/or dissipating vibrational energy, for example. Various attributes can affect the acoustic properties of such vibration-attenuating components, including their overall mass, composition, density, stiffness, thickness and location, to name a few.